Multiple radars on chip-based systems

ABSTRACT

A multiple radar on chip based system is disclosed in the present invention which mainly comprises a ramp generator which is configured to input and process a digital signal and convert it into a digital ramp signal. The fractional-N PLL synthesizer receives the digital ramp signal from the ramp generator and compares it with reference input signal to provide analog RF ramp signal. A frequency multiplier is provided to receive the analog RF ramp signal from the fractional N-PLL synthesizer and generates a local oscillator output signal which is sent to a plurality of receiver chains as output signal. These receiver chains receive amplified analog signal input from the power amplifier also as an output and then after comparing the frequency of local oscillator output and amplified analog signal input, final output is processed. The ramp generator and fractional-N PLL synthesizer may be off chip.

TECHNICAL FIELD

The present invention generally relates to radar based systems by integrating transmitter and receiver channels of the radar system on a single semiconductor radar chip.

BACKGROUND

Radar is a detection system that uses radio waves to determine the range, angle, or velocity of objects. It consists of a transmitter producing electromagnetic waves in the radio or microwaves domain, a transmitting antenna and a receiver and processor to determine properties of the objects. Radio waves from the transmitter reflect off the object and return to the receiver, giving information about the objects location and speed.

Radar systems are often characterized by the number of transmitters and receivers channels they possess. In the past several years, technology has evolved to the point that it is now possible to integrate a complete radar system into a single semiconductor chip, which includes power amplifiers, receiver chains, frequency multipliers, PLL (Phase locked loop) synthesizer and ramp generators. The radar system measures the bearing and distance of the obstacles that approach in their path while also displaying the weather condition information and give accurate altitude readings for navigation. Radar is also use for monitor precipitation and wind by meteorologists and has become a primary tool for short-term weather forecasting analysing thunderstorms, tornadoes, winter storms, precipitation types etc. Geologists also use specialized ground-penetrating radars to map the composition of earth's surface. Police forces use radar guns to monitor vehicle speeds on the roads. Smaller radar systems are used to detect human movement, Automatic door opening, light activation and intruder sensing.

While integrating multiple transmitter and receiver channels on the same ROC (Radar on chip) increases the performance of the radar, it also increases the size of the die, its cost and its complexity. Moreover, it limits its flexibility. While having many transmitter or receiver channels is necessary for a ROC integrated in a system for high end applications, a ROC with less transmitter or receiver chains might be enough for less critical applications.

Hence there is a strong need and demand for the creation of systems using combination of multiple scalable ROC's that are powerful and contain as many transmitter or receiver chains as needed, while at the same time supporting systems for less demanding applications.

SUMMARY

The present invention overcomes the above problem of increase in the size of the die, its cost and limited flexibility by providing a system which is powerful and contains as many transmitter or receiver chains as needed and supporting systems for less demanding applications utilizing combination of multiple scalable radar on chips.

In accordance with the first aspect of the present invention, an embodiment herein describes the architecture of the scalable radar on chip. The SROC (Scalable radar on chip) architecture mainly comprises four parts—a fractional-N PLL synthesizer, a digital ramp generator, a Tx (Transmitter) section composed of a frequency multiplier and Y number of transmitter chains and an Rx (Receiver) section composed of Z number of receiver chains based on a homodyne architecture.

In accordance with the second aspect of the present invention, the fractional N-PLL synthesizer can be based on a standard controller where the N-division factor is controlled by a delta-sigma modulator to obtain a division factor that cannot be an integer. The fractional N-PLL synthesizer comprises several components such as R-divider, phase comparator, charge pump, low-pass filter, VCO (Voltage controlled oscillator), prescaler, fractional-N divider and delta sigma modulator.

In accordance with the third aspect of the present invention, the SROCs synthesizer provides several outputs that can be used as an input by multiple transmitter sections which is one of the main characteristics of the SROC design that allows its use in an array-configuration of identical elements. The preferred embodiment herein describes a system obtained using two SROCs to create a radar system with double the number of transmitter and receiver channels of a single ROC. Reducing the number of transmitter and receiver of the SROC drives down both its engineering and manufacturing costs. This is of paramount importance for low end applications, where a low number of transmitter or receiver channels might be required. The larger number of transmitter or receiver channel is bound only by the number of SROCs that can be placed in an array, which in turn is determined by the number (W) of outputs of the PLL synthesizer block.

In accordance with the fourth aspect of the present invention, the SROC architecture mainly comprises a Tx (Transmitter) section composed of a Y number of transmitter chains and an Rx (Receiver) section composed of Z number of receiver chains based on a homodyne architecture, while ramp generator and PLL synthesizer are off chip and frequency multiplier can be on chip or absent.

These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments herein will be better understood from the following detailed description with reference to the drawings, in which:

FIG. 1 illustrates the internal architecture of scalable radar on chip system;

FIG. 2 illustrates the block diagram of a fractional-N PLL synthesizer; and

FIG. 3 illustrates the internal architecture of multiple scalable radar on chip system in a two-array configuration;

FIG. 4 illustrates a further embodiment of the internal architecture of multiple scalable radar on chip.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practised and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

The embodiments herein achieve this by providing a system which is powerful and contain as many transmitter or receiver chains as needed, and supporting systems for less demanding applications utilizing combination of multiple scalable radar on chips.

FIG. 1 is a block diagram illustrating a SROC system 100 internal architecture according to one embodiment of the present invention. The SROC system 100 comprises a ramp generator 104 configured to input a digital signal 102 and process it. The digital signal 102 gets converted to digital ramp signal 102 a after processing, which then passes through a fractional-N PLL synthesizer 106 having a reference input 102 d. The fractional-N PLL synthesizer 106 provides several outputs in the form of W number of analog RF (Radio frequency) ramp signals 102 c. A analog RF ramp signal 102 c is then passed to a frequency multiplier 108 of transmitter section comprising of Y number of transmitter chains 112. The frequency multiplier 108 generates an output signal whose output frequency is a multiple of its input frequency. A LO (Local oscillator) signal is generated for the up and down conversion of the RF ramp signal 102 b. The RF ramp signal 102 b from frequency multiplier 108 is passed to a power amplifier 110 where the RF ramp signal 102 b is amplified and provided sufficient output power. This amplified RF ramp output signal is being passed to the transmitter section comprising of Y number of transmitter chains 112 from where it is being passed to the Z number of receiver chains 114 a of the receiver section 114 and output 116 is being processed.

FIG. 2 is a block diagram illustrating architecture of fractional N-PLL synthesizer 106 according to second embodiment of the present invention. The fractional N-PLL synthesizer 106 is based on a standard PLL controller where the N division factor is controlled by a delta sigma modulator 204 to obtain a division factor that cannot be an integer. A reference input 102 d in the form of a digital signal is provided to the R-divider 210 which further passes the reference input 102 d to phase comparator 208. Another digital ramp input 102 a is passed to the delta sigma modulator 204 which produces a bitstream wherein the average level of this bitstream represents the input signal level. The signal then passes to fractional-N divider 206 from where it reaches the phase comparator 208. The phase comparator 208 generates a voltage signal which represents the difference in phase between two signal inputs. The loop will lock when the two signals entering the phase comparator 208 are of the same frequency. The low pass filter 214 receives the signal through the charge pump 212 which lowers or raises the voltage by storing charge in the form of energy. The low pass filter 214 passes signals with a frequency lower than a certain cut off frequency and attenuates signals with frequencies higher than the cut-off frequency. The VCO (Voltage controlled oscillator) 216 after receiving the signal from low pass filter 214 performs frequency modulation and processes the signal to give a plurality of RF ramp signals as an output. The prescaler 218 is used to generate an output signal of a frequency taking an input signal of a frequency.

FIG. 3 is a block diagram illustrating the internal architecture of multiple scalable radar on chip system in a multi-array configuration according to third embodiment of the present invention. The multi-array configuration of two SROCs mainly comprises first SROC and second SROC. The first SROC further comprises a ramp generator 304, fractional N-PLL synthesizer 306, frequency multiplier 308, power amplifier 310, Y number of transmitter chains 312, Z number of receiver chains 314 a and receiver section 314. The second SROC further comprises a ramp generator 104, fractional N-PLL synthesizer 106, frequency multiplier 108, power amplifier 110, Y number of transmitter chains 112, Z number of receiver chains 114 a and receiver section 114. The ramp generator 104 of the second SROC is used to drive the fractional-N PLL synthesizer 306 of the first SROC, which in turn produces the RF ramps required to drive both first and second SROCs. In this example, the ramp generator 304 of the first SROC and the fractional-N PLL synthesizer 106 of the second SROC are not used. The system obtained in this example uses two SROCs to create a radar system with double the number of Tx and Rx channels of a single SROC. The above architecture can be extended to obtain the required number of Rx and Tx channels, by combining the adequate number of SROCs up to W, which is the number of outputs of the PLL synthesizer block 306.

FIG. 4 is a block diagram illustrating the internal architecture of multiple scalable radar on chip system in a multi-array configuration according to a fourth embodiment of the present invention. The multi-array configuration of two SROCs mainly comprises first SROC and second SROC, an off-chip ramp generator 104 and an-off chip fractional N-PLL synthesizer 106. The first SROC comprises frequency multiplier 308, power amplifier 310, Y number of transmitter chains 312, Z number of receiver chains 314 a and receiver section 314. The second SROC further comprises frequency multiplier 108, power amplifier 110, Y number of transmitter chains 112, Z number of receiver chains 114 a and receiver section 114. The frequency multipliers 108, 308 may be absent in certain application in which there is no need for multiplication of frequency. The ramp generator 104 is used to drive the fractional-N PLL synthesizer 106 which in turn produces the RF ramps required to drive both first and second SROCs. The system obtained in this example uses two SROCs to create a radar system with double the number of Tx and Rx channels of a single SROC. The above architecture can be extended to obtain the required number of Rx and Tx channels, by combining the adequate number of SROCs up to W, which is the number of outputs of the PLL synthesizer 106.

As mentioned, there remains the foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments.

It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only. Changes may be made in the details, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. 

1. A scalable radar on chip (SROC) based system comprising: a ramp generator configured to input and process a digital signal and convert it into digital ramp signal; a fractional-N PLL synthesizer receiving the digital ramp signal from the ramp generator and comparing the digital ramp signal with reference input signal to provide analog RF ramp signal; a frequency multiplier receiving the analog RF ramp signal from the fractional-N PLL synthesizer and generating a local oscillator output signal; a power amplifier receiving the analog output signal from the frequency multiplier and amplifying it to output signal; a transmitter section transmitting the amplified analog output signal received from the power amplifier; a receiver section receiving the amplified analog output signal from the transmitter section; and a plurality of receiver chains receiving the amplified analog output signal from the receiver section and local oscillator signal from the frequency multiplier as output signals and processing the final output signal.
 2. The system as claimed in claim 1, wherein the fractional-N PLL synthesizer provides plurality of outputs in the form of analog RF ramp signal.
 3. The system as claimed in claim 1, wherein the fractional-N PLL synthesizer provides a single output in the form of analog RF ramp signal.
 4. The system as claimed in claim 1, wherein the ramp generator is a digital ramp generator used to drive the fractional-N PLL synthesizer.
 5. The system as claimed in claim 1, wherein the fractional-N PLL synthesizer is based on a standard PLL controller where the N-division factor is controlled by a delta-sigma modulator to obtain a division factor that cannot be an integer.
 6. The system as claimed in the claim 1, wherein the fractional-N PLL synthesizer produces W number of RF ramp signals as output.
 7. The system as claimed in claim 6, wherein the W number of RF ramp signals as output are used as input by multiple Tx sections.
 8. The system as claimed in claim 1, wherein the fractional-N PLL synthesizer has a reference input.
 9. The system as claimed in claim 8, wherein the reference input is obtained from an element internal to the radar on chip based system.
 10. A scalable radar on chip based system comprising: an off chip fractional-N PLL synthesizer receiving a digital ramp signal from an off chip ramp generator and comparing the digital ramp signal with reference input signal to provide analog RF ramp signal; a power amplifier receiving the analog RF ramp signal from the off chip fractional-N PLL synthesizer and amplifying it to output signal; a transmitter section transmitting the amplified analog output signal received from the power amplifier; a receiver section receiving the amplified analog output signal from the transmitter section; and a plurality of receiver chains receiving the amplified analog output signal from the receiver section and processing the final output signal.
 11. The system as claimed in claim 10, further comprising on chip frequency multiplier receiving the analog RF ramp signal from the off chip fractional-N PLL synthesizer.
 12. A multiple scalable radar on chip (SROC) based system in a multi-array configuration comprising: ramp generator of a first SROC driving the fractional-N PLL synthesizer of a second SROC; and fractional N-PLL synthesizer of the second SROC producing RF ramp signals to drive both first and second SROCs.
 13. The system as claimed in claim 12, wherein the multi-array configuration of SROCs comprises first SROC as master SROC and second SROC as slave SROC.
 14. The system as claimed in claim 12, wherein the W number of SROC can be configured together in an array comprising one master SROC and at least one slave SROC.
 15. The system as claimed in claim 12, wherein multi-array increases the number of Tx and Rx channels of a single SROC.
 16. The system as claimed in claim 12, wherein multi-array configuration of two SROCs is used to create a radar system with double number of transmitter and receiver channels of a single SROC.
 17. The system as claimed in claim 12, wherein required number of transmitter and receiver channels is obtained by combining the adequate number of SROCs up to W, which is the number of outputs of the fractional-N PLL synthesizer.
 18. The system as claimed in claim 12, wherein the ramp generator of the first SROC and the fractional-N PLL synthesizer of second SROC are left unused.
 19. A scalable radar on chip (SROC) based method, the method comprising: inputting the digital signal to the ramp generator for the generation of the ramp signal; supplying the ramp signal to the fractional-N PLL synthesizer to the generation of the RF ramp signal; increasing the frequency of the RF ramp signal by the frequency multiplier; amplifying the RF ramp signal using power amplifier; transmitting the amplified RF ramp signal by transmitter section; receiving the signal by the receiver chain; and processing the signal to obtain radar output. 